JavaScript Foundations

Question

This question is from a timed JavaScript Challenge.

What is the output of this code?

var f = [
function(a, b) { return a + b },
function(a, b) { return a - b },
function(a, b) { return a * b },
function(a, b) { return a / b },
function(a, b) { return a % b }
];

var x = f[0] (4, 6);
var x = f[3] (x, 2);
var x = f[4] (18, x);

The output is 3.

I understand the output. My question is, is this an example of an array, an object, and a method all in one?

Answer 1

We will start with the building block — function.

Basically it's just a wrapper of multiple statements which group together and possibly with a return value. Besides, we can call it by its name.

When we are talking about methods then you may think of it like a function as well, but attaching to an object.

You may find more information at:-
https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Functions/Method_definitions

Answer 2

I don't understand how that x value becomes 3 in the end, to my understanding, f[0] is the one that returns result of a + b. Here's how I read the code, please guys, correct me if I misunderstood how it's done ; )

1. x = 4 + 6 => 10
2. x = x + 2 => 12
3. x = 18 + x => 30

Did I miss anything here, any input/correction is appreciated.

TIA,

Answer 3

Oh that's quite alright, for a moment there I thought I was losing my mind, but now it's clear :D

Thanks for clarification and confirmation ...

Answer 4

YES, almost everything in JavaScript can be treated as an object, including functions. 😉

Answer 5

Zephyr Koo Thank you for explaining. Can you explain a little about methods? Methods are actions performed on objects. So because the object completes calculations, this makes it a method?

Answer 6

Ipang I made a mistake writing in the challenge question but fixed it. Thanks/sorry!

Zephyr Koo Thank you!

Answer 7

DumbledoresAmy You're welcome! 😉